iPhone 5 not vibrating, tried new vibrator and cable

Hello ifixit,

Today I have an iPhone 5 that I can not get to vibrate for the life of me. I received the phone with the complaint of no vibration. As far as I know, we didn't work on anything else on the phone and it is not water damaged. Everything looks pristine inside. We tried a several new vibrators and volume cables on the phone, so I believe it is more of a PCB issue. With several different volume cables hooked up, we tested the voltage coming out of the gold contacts on the volume cable. It only reads about 0.01-0.02 volts. I don't remember how much it should normally be, but its definitely higher than that. Also it has been confirmed that nothing is in the way of the vibrator or grounding it out. So what I'm asking is, where should I head on the PCB to find the root cause of this issue? Is there a certain set of fuses? And how do I tell if something is shorted in the voltage supply line for the vibrator?

Thanks in advance